Which Time Infotype is for different payment rate in time?

I have a business request, The business is paying employees differently when the acting on higher position. The use manual calculation is based on the following formula : acting payscale - current pay scale = Difference. They take Hours from ZL table per Time WT and they multiply by difference between 2 payscale and gives total amt for acting.

One way you can do this is via a substitution infotype IT2003 and the different payment option.

If you have your pay rates set up on T510 then you can maintain position codes on T528B and link them via Pay Scale type/area/group.

Then when you enter a substitution on a day with one of these positions then payroll will use the rate relating to that position for time wage types entered for that day (assuming you have it all set up correctly!)